1. Field of the Invention
Individuals subject to cataractogenic radiation, both short and long term exposure, suffer eye damage. This damage manifests itself primarily as a tumor and a nuclear or cortical lens cataract. The lens cataractogenic dose has been recently identified as 200 REMS with Gamma or X-radiation for acute exposure and between 450 REMS and 750 REMS for fractionated exposure. Damage to an eye begins at the time of the exposure, and continues to occur for several weeks thereafter, due to the generation of free radical toxins in the eye tissue. Secondary to X-ray induced cataracts, concurrent or subsequent exposure to Ultra-Violet (UV) light will cause photochemical cataracts, while reducing the cataractogenic dose for all types of radiation. Therefore, the danger is increased whenever more than one type of harmful radiation exposure to the eye exists with cumulative effects. Also, shorter wavelength infrared radiation will promote cataract formation. Such an infrared cataract has been termed a glass blower's cataract.
At risk are dental patients undergoing various procedures (including C.T. scan, fluoroscopic, tomographic, cephalometric, panagraphic, full mouth series, bite wing, and occlusal X-ray procedures, and UV radiation induced curing processes), medical patients (as with C.T. scan, fluoroscopic, tomographic, and like techniques), and the dental and medical practioners performing radiation related procedures. Additional at risk individuals include airline pilots, astronauts, people living at higher elevations, nuclear accident or conflict victims, and those persons found in environments where radiation is prevalent.
Various protective eye wear devices exist, but not for reducing all types of cataractogenic radiation, while providing for interdiciplinary use. In each case, only one form of harmful radiation is stopped, allowing the other forms to damage the eye. Combination Gamma, UV, X-radiation, and near blue light protective goggles are desperately needed. The subject invention structure provides the combined protection while incorporating additional desirable elements. More particularly, this device relates to sterilizable goggles having a novel composition and construction comprising a frameless, circularly curved leaded polymer, Gamma, UV, near blue light, and X-ray opaque, yet visible light transmissive lens having an outer perimeter edge associated with a leaded vinyl radiation opaque boot, adjustable and interchangable ear pieces, and a detachable variably sized nose rest.
2. Description of the Background Art
Given sufficient exposure, most radiation is capable of inducing damage to sensitive eye tissue. However, it is documented that the most dangerous range of radiation (in terms of generating tumors, cataracts, and general retinal injury) is near blue visible light and wavelengths less than 525 nm, such as UV-A (320-400 nm), UV-B (280-320 nm), and UV-C (180-280 nm) in the case of photochemical cataract (see, The New England Journal of Medicine, H. R. Taylor, et al., 319(22), pp. 1429-1433 (1988) and Documenta Ophthalmologica, S. Zigman, 55, pp. 375-391 (1983)), and Gamma and X-ray (see, Pathology of the Eye, D. vonDomarus, et al., pp. 227-234, Springer-Verlag, New York (1986), Oral Surgery, S. Antoku, et al., 41(2), pp. 251-260 (1976), Radiation Physics, J. T. Littleton, et al., 129, pp. 795-798 (1978), and Ophthalmology, L. T. Chylack, Jr., 91(6), pp. 596-601 (1984)). Additionally, the foregoing articles establish a cause and effect relationship between radiation exposure and eye damage (tumor, cataract, and retinal injury), while providing data of actual measured dose exposure to eye tissue in REMS (biological equivalent of radiation absorbed dose: ionizing energy transfer of 100 ergs per gram of eye tissue) resulting from irradiation procedures and environmental exposure.
Until now, the problem of combined and cumulative effect multi-type radiation exposure of the eye has not been solved. Traditionally, protective eye devices for preventing UV and X-radiation damage are either totally opaque to visible light, such as a shield of lead foil, or transmissive to visible light and selectively restrictive to either UV or X-radiation. Additionally, most of the prior art devices are not suited for interdiciplinary use because they are cumbersome and heavy, thereby inhibiting easy movement of the wearer, while failing to protect from all angles of exposure.
In general, medical and dental patients fear what they can not see. Some of the prior devices overlooked the desirability and necessity of having a patient observe a procedure so that they may be aware of and respond to spatial commands of head positioning. Due to undesirable angles and construction features, many of the prior art designs that relied on complete visible light, UV and X-ray blockage are not adaptable to visible light transmissive versions. In addition, the problem of lens fogging with condensation occurs with prior art goggles that provide peripheral exposure protection. Further, the prior art goggles do not shield the eyes from all types of cataractogenic radiation.
Disclosed in U.S. Pat. No. 4,024,405 is an X-ray eye shield for protecting eye tissue during dental radiography. The lens cups are constructed of lead encased plastic. These lens cups fit snugly over the patient's eye sockets, therefore, all visible, UV, and X-ray radiation is blocked and the free circulation of condensation preventing air is stopped and fogging occurs.
U.S. Pat. No. 4,635,625 relates a surgical eye mask for laser treatment fabricated from highly reflective metal, preferably aluminum, foil and having eye pads of cotton gauze for maintaining eye moisture. Adhesive means are provided to seal the mask against the patient's face during laser irradiation. Given the radiolucent qualities of aluminum foil, X-radiation is not adequately blocked and all vision is completely blocked.
A hand-held light filter is presented in U.S. Pat. No. 4,640,685. This shield must be held by a dental assistant in front of a patient's mouth during UV irradiation procedures involved in curing dental resins in the patient's mouth. From particular angles, incident scatter UV light may be reflected by the shield back into the patient's eyes with harmful effects. In addition, harmful radiation of less than 400 nm or greater than 525 nm (near blue light) is free to pass through the specific material disclosed in '685.
Depicted in U.S. Pat. No. 4,701,129 is a visible light transmissive face shield device for protecting a dentist's face from debris, bacteria, and the like, including UV radiation from resin curing procedures. Large shoulder supports hold the device in place during use and restrict movement.
U.S. Pat. No. 4,758,079 discloses an eye shield that resembles a pair of ordinary sunglasses. However, the lenses in the device are coated with reflecting and absorbing materials that completely block only direct UV and visible light transmission, while allowing harmful peripheral scatter rays to reach the eye. Additionally, the lens material does not effectively block X-radiation.
Offered for sale in Catalog G-5 from Nuclear Associates (A Division of Victoreen, Inc., 100 Voice Road, Carle Place, NY, 11514-1593) are two types of visible and UV light transmissive, but X-ray opaque glasses. On page 34 is offered, for medical personnel, prescription and nonprescription Radiglasses.TM. which resemble normal eyeglasses with side shields of the same X-ray opaque heavy leaded glass as used in the front viewing lenses. Close examination reveals that complete peripheral ray protection from many angles is not provided. Additionally, the X-ray opaque frame interferes with the images of important anatomical landmarks necessary for diagnosis in medicine and dentistry. A set of protective lens cups for a patient are offered alternatively on page 48. These lens cups fit tightly over the contours of the orbits of the eye to block peripheral radiation, thereby preventing the exchange of moist air to produce fogging.